A conventional gravity-operated flush toilet has several basic components. The porcelain or china components include a bowl and a water tank mounted on top of a rear portion of the bowl. The bowl and tank are usually separate pieces bolted together to form a so-called two-piece toilet. Modern gravity-operated flush toilets are frequently made as a so-called one-piece toilet in which the bowl and tank are made as one continuous integral piece of china.
The plumbing components of a gravity-operated flush toilet include a fill valve in the tank which is connected to a water supply line, a flush valve surrounding a drain hole in the bottom of the tank that communicates with the bowl, and a flapper valve that normally closes and seals the flush valve. The plumbing components further include a control such as a pushbutton or lever mounted on a wall of the tank that moves a lever whose remote end is connected to the flapper valve for lifting the same.
In the experience of these inventors, a water flow adjuster may be interposed between a toilet fill valve and the overflow tube of a flush valve. The water flow adjuster may comprise a flow device with means for controlling flow that ranges from fully open to fully closed (i.e., where flow is stopped). In the art of toilet fill valves, however, the use of such a device is desirable and particularly where the flow can be carefully controlled. Accordingly, there is a need to provide a flow control device combined with a means for carefully and more precisely controlling the flow ratio. There is also a need to provide such a flow adjuster and control means that allows a toilet installer to mechanically adjust the percentage of toilet bowl fill using a numbering system where the key numbers correspond to specific toilets and/or to specific refill amounts.